The construct of adaptive style provides a heuristic model for understanding the frequently reported findings of lower self-reports of psychological distress in children with cancer, in comparison to healthy children. Assessment of adaptive style allows for differentiation between truly low anxious individuals, who accurately report low levels of distress, and repressors, who maladaptively avoid the perception of negative affect of distress. In adults, repressive adaptation has been associated with altered patterns of physiological response to stress, and is related to numerous adverse health outcomes. Such relationships have not yet been studied in children. Recent studies have demonstrated a significantly higher incidence of repressors in children with cancer relative to healthy children, which accounts, in part, for the lower levels of distress by self-report in these children. Given the higher incidence of repressive adaptation in children with cancer, adaptive style may be a particularly important predictor of health outcomes in this population. The present proposal aims to improve measurement of adaptive style in children by combining self-report and psychophysiological assessment techniques, while examining the clinical significance of adaptive style in children undergoing treatment for cancer. The specific aims of the project are: 1) To determine the physiological concomitants of adaptive style in healthy children and children with cancer; 2) To assess the concordance in measurement of adaptive style by self-report and physiological indices; and 3) to determine the relationship of adaptive style to tolerance of anti-cancer therapy in children with recently diagnosed malignancies. These aims will be accomplished through two related studies. Study 1 will use a two group, case control design, pairing children who have completed treatment for cancer with healthy children matched on age, race, and gender. Participants will complete a battery of self report measures assessing adaptive style and then undergo physiological monitoring (heart rate, blood pressure, muscle tension, skin conductance, salivary cortisol) in a laboratory stress assessment task. Study 2 utilizes a single group, short term longitudinal design to determine the significance of adaptive style as a predictor of tolerance to anti-cancer therapy in terms of treatment side effects, acute toxicities and medical complications. Newly diagnosed pediatric cancer patients will undergo an identical procedure of self-report measures, stress tasks, and physiological assessment to assess adaptive style, and then be followed prospectively for 6 months while on active therapy. This study will advance knowledge regarding adaptive style in children, which can help to improve identification of truly distressed and non-distressed children, as well as those who may be at high risk for adverse healthy outcomes as a function of adaptive style.